Elastofibrolipoma of the mediastinum. A previously undescribed benign tumor containing abnormal elastic fibers.

We report the case of a 57-year-old woman who was found to have a mass in the anterior mediastinum. Surgical excision of the mass revealed a well-delimited lesion 10 cm in largest diameter. Histologically, the mass was composed of mature fat alternating with sclerotic connective tissue, which also contained extensive eosinophilic deposits, similar to the abnormal elastic fibers seen in elastofibroma dorsi. The elastic nature of these deposits was confirmed by elastic staining and electron microscopy. We consider this lesion, which we named elastofibrolipoma, a true benign neoplasm that is characterized by tumoral elastogenesis.